Estrabismo, acuidade visual e erro refrativo não corrigido na criança em idade escolar

Preventable visual loss in children is an important public health problem. The critical period of susceptibility to deprivation or abnormal visual experience has been identified since the early 1970s. Preventable visual loss caused by amblyopia (0.3%–4%) and its risk factors such as strabismus (2.1%–4.6%) and uncorrected refractive errors (5%–7.7%) represent an important public health problem. Thus the primary justification for preschool vision screening is the detection of amblyopia or amblyogenic refractive, strabismic, or ocular disease conditions. However in Portugal there has been little investigation regarding prevalence of visual anomalies among school-age children. Data on the prevalence are lacking but are needed for planning vision services. Aims: 1) Determine the prevalence of strabismus; 2) Determine the prevalence of decreased visual acuity; 3) Determine the prevalence of uncorrected refractive error.

Lighting conditions and optical filters effects on visual performance of speleologists exposed to cave environments

The aim of this study is to evaluate lighting conditions and speleologists’ visual performance using optical filters when exposed to the lighting conditions of cave environments. A crosssectional study was conducted. Twenty-three speleologists were submitted to an evaluation of visual function in a clinical lab. An examination of visual acuity, contrast sensitivity, stereoacuity and flashlight illuminance levels was also performed in 16 of the 23 speleologists at two caves deprived of natural lightning. Two organic filters (450 nm and 550 nm) were used to compare visual function with and without filters. The mean age of the speleologists was 40.65 (± 10.93) years. We detected 26.1% participants with visual impairment of which refractive error (17.4%) was the major cause. In the cave environment the majority of the speleologists used a head flashlight with a mean illuminance of 451.0 ± 305.7 lux. Binocular visual acuity (BVA) was -0.05 ± 0.15 LogMAR (20/18). BVA for distance without filter was not statistically different from BVA with 550 nm or 450 nm filters (p = 0.093). Significant improved contrast sensitivity was observed with 450 nm filters for 6 cpd (p = 0.034) and 18 cpd (p = 0.026) spatial frequencies. There were no signs and symptoms of visual pathologies related to cave exposure. Illuminance levels were adequate to the majority of the activities performed. The enhancement in contrast sensitivity with filters could potentially improve tasks related with the activities performed in the cave.

Função visual e desempenho na leitura em crianças do 1º ciclo do ensino básico do concelho de Lisboa

RESUMO - Esta tese pretende ser um contributo para o estudo das anomalias da função visual e da sua influência no desempenho da leitura. Apresentava como objetivos: (1) Identificar a prevalência de anomalias da função visual, (2) Caracterizar o desempenho da leitura em crianças com e sem anomalias da função visual, (3) Identificar de que modo as anomalias da função visual influenciam o desempenho da leitura e (4) Identificar o impacto das variáveis que determinam o desempenho da leitura. Foi recolhida uma amostra de conveniência com 672 crianças do 1º ciclo do ensino básico de 11 Escolas do Concelho de Lisboa com idades compreendidas entre os 6 e os 11 anos (7,69±1,19), 670 encarregados de educação e 34 Professores. Para recolha de dados, foram utilizados três instrumentos: 2 questionários de perguntas fechadas, avaliação da função visual e prova de avaliação da leitura com 34 palavras. Após observadas, as crianças foram classificadas em dois grupos: função visual normal (FVN=562) e função visual alterada (FVA=110). Identificou-se uma prevalência de 16,4% de crianças com FVA. No teste de leitura, estas crianças apresentaram um menor número de palavras lidas corretamente (FVA=31,00; FVN=33,00; p<0,001) e menor precisão (FVA=91,18%; FVN=97,06%; p<0,001). Esta tendência também foi observada na comparação entre os 4 anos de escolaridade. As crianças com função visual alterada mostraram uma tendência para a omissão de letras e a confusão de grafema. Quanto à fluência (FVA=24,71; FVN=27,39; p=0,007) esta foi inferior nas crianças com FVA para todos os anos de escolaridade, exceto o 3º ano. As crianças com hipermetropia (p=0,003) e astigmatismo (p=0,019) não corrigido leram menos palavras corretamente (30,00; 31,00) e com menor precisão (88,24%; 91,18%) que as crianças sem erro refrativo significativo (32,00; 94,12%). A performance escolar classificada pelos professores foi inferior nas crianças com FVA e mais de ¼ necessitavam de medidas de apoio especial na escola. Não se verificaram diferenças significativas na performance da leitura das crianças com FVA por grupos de habilitações dos encarregados de educação. Verificou-se que o risco de ter um desempenho na leitura alterado é superior [OR=4,29; I.C.95%(2,49;7,38)] nas crianças que apresentam FVA. Relativamente ao 1º ano de escolaridade, o 2º, 3º e 4º anos apresentam um menor risco de ter um desempenho na leitura alterado. As variáveis método de ensino, habilitações dos encarregados de educação, tipo de escola (pública/privada), idade do Professor e número de anos de experiência do Professor, não foram fatores estatisticamente significativos para explicar a alteração do desempenho na leitura, quando o efeito da função visual se encontra contemplado no modelo. Um mau desempenho na leitura foi considerado nas crianças que apresentaram uma precisão inferior a 90%. Este indicador pode ser utilizado para identificar crianças em risco, que necessitam de uma observação Ortóptica/Oftalmológica para confirmação ou exclusão da existência de alterações da função visual. Este trabalho constitui um contributo para a identificação de crianças em desvantagem educacional devido a anomalias da função visual tratáveis, propondo um modelo que pretende orientar os professores na identificação de crianças que apresentem um baixo desempenho na leitura.

Efficacy of a gas permeable contact lens to induce peripheral myopic defocus

Purpose. The purpose of this work was to evaluate the potential of a novel custom-designed rigid gas permeable (RGP) contact lens to modify the relative peripheral refractive error in a sample of myopic patients. Methods. Fifty-two right eyes of 52 myopic patients (mean [TSD] age, 21 [T2] years) with spherical refractive errors ranging from j0.75 to j8.00 diopters (D) and refractive astigmatism of 1.00 D or less were fitted with a novel experimental RGP (ExpRGP) lens designed to create myopic defocus in the peripheral retina. A standard RGP (StdRGP) lens was used as a control in the same eye. The relative peripheral refractive error was measured without the lens and with each of two lenses (StdRGP and ExpRGP) using an open-field autorefractometer from 30 degrees nasal to 30 degrees temporal, in 5-degree steps. The effectiveness of the lens design was evaluated as the amount of relative peripheral refractive error difference induced by the ExpRGP compared with no lens and with StdRGP conditions at 30 degrees in the nasal and temporal (averaged) peripheral visual fields. Results. Experimental RGP lens induced a significant change in relative peripheral refractive error compared with the nolens condition (baseline), beyond the 10 degrees of eccentricity to the nasal and temporal side of the visual field (p G 0.05). The maximum effect was achieved at 30 degrees. Wearing the ExpRGP lens, 60% of the eyes had peripheral myopia exceeding j1.00 D, whereas none of the eyes presented with this feature at baseline. There was no significant correlation (r = 0.04; p = 0.756) between the degree of myopia induced at 30 degrees of eccentricity of the visual field with the ExpRGP lens and the baseline refractive error. Conclusions. Custom-designed RGP contact lenses can generate a significant degree of relative peripheral myopia in myopic patients regardless of their baselin spherical equivalent refractive error.

Strategies to regulate myopia progression with contact lenses: a review

Purpose: Higher myopic refractive errors are associated with serious ocular complications that can put visual function at risk. There is respective interest in slowing and if possible stopping myopia progression before it reaches a level associated with increased risk of secondary pathology. The purpose of this report was to review our understanding of the rationale(s) and success of contact lenses (CLs) used to reduce myopia progression. Methods: A review commenced by searching the PubMed database. The inclusion criteria stipulated publications of clinical trials evaluating the efficacy of CLs in regulating myopia progression based on the primary endpoint of changes in axial length measurements and published in peerreviewed journals. Other publications from conference proceedings or patents were exceptionally considered when no peer-review articles were available. Results: The mechanisms that presently support myopia regulation with CLs are based on the change of relative peripheral defocus and changing the foveal image quality signal to potentially interfere with the accommodative system. Ten clinical trials addressing myopia regulation with CLs were reviewed, including corneal refractive therapy (orthokeratology), peripheral gradient lenses, and bifocal (dual-focus) and multifocal lenses. Conclusions: CLs were reported to be well accepted, consistent, and safe methods to address myopia regulation in children. Corneal refractive therapy (orthokeratology) is so far the method with the largest demonstrated efficacy in myopia regulation across different ethnic groups. However, factors such as patient convenience, the degree of initial myopia, and non-CL treatments may also be considered. The combination of different strategies (i.e., central defocus, peripheral defocus, spectral filters, pharmaceutical delivery, and active lens-borne illumination) in a single device will present further testable hypotheses exploring how different mechanisms can reinforce or compete with each other to improve or reduce myopia regulation with CLs.

Alimentação e miopia

Dissertação de mestrado em Optometria Avançada

Alterações na biometria e na refração durante o ano letivo II

Dissertação de mestrado em Optometria Avançada

Análise da prevalência da miopia em estudantes universitários

Dissertação de mestrado em Optometria Avançada

Deep sclerectomy combined with trabeculectomy in pediatric glaucoma

Résumé : Ce travail porte sur l'étude rétrospective d'une série de jeunes patients opérés de glaucomes pédiatriques. Le but est d'évaluer le résultat au long cours d'une intervention chirurgicale combinant une sclérectomie profonde et une trabéculectomie (sclérectomie profonde pénétrante). Durant la période de mars 1997 à octobre 2006, 28 patients on été suivis pour évaluer le résultat de cette chirurgie effectuées sur 35 yeux. Un examen ophtalmologique complet a été pratiqué avant la chirurgie, 1 et 7 jours, puis 1, 2, 3, 4, 6, 9, 12 mois, enfin tous les 6 mois après l'opération. Les critères d'évaluation du résultat postopératoire sont : les changements de pression intraoculaire, le traitement antiglaucomateux adjuvant, le taux de complication, le nombre de reprises chirurgicales,- l'erreur de réfraction, la meilleure acuité visuelle corrigée, l'état et le diamètre de la cornée. L'âge moyen est de 3.6 ± 4.5 ans et le suivi moyen de 3.6 ± 2.9 ans. La pression intraoculaire préopératoire de 31.9 ± 11.5 mmHg baisse de 58.3% (p<0.005) à la fin du suivi. Sur les 14 patients dont l'acuité visuelle a pu être mesurée, 8 (57.1 %) ont une acuité égale ou supérieure à 5/10e, 3 (21.4%) une acuité de 2/10e après intervention. Le taux de succès cumulatif complet à 9 ans est de 52.3%, le succès relatif 70.6%. Les complications menaçant la vision (8.6%) ont été plus fréquentes dans les cas de glaucome réfractaire. Pour conclure la sclérectomie profonde combinée à une trabéculectomie est une technique chirurgicale développée afin de contrôler la pression intraoculaire dans les cas de glaucomes congénitaux, juvéniles et secondaires. Les résultats intermédiaires sont encourageants et prometteurs. Les cas préalablement opérés avant cette nouvelle technique ont cependant un pronostic moins favorable. Le nombre de complications menaçant la vision est essentiellement lié à la sévérité du glaucome et au nombre d'interventions préalables. Abstract : Purpose : To evaluate the outcomes of combined deep sclerectomy and trabeculectomy (penetrating deep sclerectomy) in pediatric glaucoma. Design : Retrospective, non-consecutive, non-comparative, interventional case series. Participants : Children suffering from pediatric glaucoma who underwent surgery between March 1997 and October 2006 were included in this study. Methods : A primary combined deep sclerectomy and trabeculectomy was performed in 35 eyes of 28 patients. Complete examinations were performed before surgery, postoperatively at 1 and 7 days, at 1, 2, 3, 4, 6, 9, 12 months and then every 6 months after surgery. Main Outcome Measures : Surgical outcome was assessed in terms of intraocular pressure (IOP) change, additional glaucoma medication, complication rate, need for surgical revision, as well as refractive errors, best corrected visual acuity (BCVA), and corneal clarity and diameters. Results : The mean age before surgery was 3.6 ± 4.5 years, and the mean follow-up was 3.5 ± 2.9 years. The mean preoperative IOP was 31.9 ± 11.5 mmHg. At the end of follow-up, the mean IOP decreased by 58.3% (p<0.005), and from 14 patients with available BCVA 8 patients (57.1 %) achieved. 0.5 (20/40) or better, 3 (21.4%) 0.2 (20/100), and 2 (14.3%) 0.1 (20/200) in their better eye. The mean refractive error (spherical equivalent) at final follow-up visits was +0.83 ± 5.4. Six patients (43%) were affected by myopia. The complete and qualified success rates, based on a cumulative survival curve, after- 9 years were 52.3% and 70.6%, respectively (p<0.05). Sight threatening complications were more common (8.6%) in refractory glaucomas. Conclusions : Combined deep sclerectomy and trabeculectomy is a surgical technique developed to control IOP in congenital, secondary and juvenile glaucomas. The intermediate results are satisfactory and promising. Previous classic glaucoma surgeries performed before this new technique had less favourable results. The number of sight threatening complications is related to the severity of glaucoma and number of previous surgeries.

Intravitreal ranibizumab (Lucentis) for the treatment of myopic choroidal neovascularization.

BACKGROUND: Macular choroidal neovascularization (CNV) is one of the most vision-threatening complications of myopia, which can lead to severe vision loss. The purpose of this study was to evaluate the safety and efficacy of intravitreal ranibizumab in the treatment of myopic CNV. METHODS: We conducted a prospective, consecutive, interventional study of patients with subfoveal or juxtafoveal CNV secondary to pathologic myopia (PM) treated with intravitreal injection of ranibizumab in the Jules Gonin University Eye Hospital from June 2006 to February 2008. Best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and fluorescein angiography (FA) were performed at baseline and monthly for all patients. Indications for retreatment were loss in BCVA associated either with persistent leakage from CNV shown on FA, and/or evidence of CNV activity on OCT. RESULTS: The study included 14 eyes of 14 patients. The mean spherical equivalent refractive error was -12.5 (range, -8.0 D to -16.0 D). Mean time of follow-up was 8.4 months (range from 3 to 16 months, SD: 3). The mean number of intravitreal injections administered for each patient was 2.36 (SD 1.5). The mean initial visual acuity (VA) was 0.19 decimal equivalent (log-MAR: 0.71, SD: 0.3). A statistically significant improvement to a mean VA of 0.48 decimal equivalent (log-MAR:0.32, SD: 0.25) was demonstrated at the final follow-up. VA improved by a mean of 3.86 (SD 2.74) lines. Nine patients (64%) demonstrated a gain of 3 or more lines. Mean central macular thickness (CMT) measured with OCT was 304 microm (SD: 39) at the baseline, and was reduced significantly at the final follow-up to 153 microm (SD: 23). Average CMT reduction was 170 microm (SD: 57). No injection complications or drug-related side effects were noted during the follow-up period. CONCLUSIONS: In this small series of eyes with limited follow-up, intravitreal ranibizumab was a safe and effective treatment for CNV secondary to PM, resulting in functional and anatomic improvements.

Deep sclerectomy combined with trabeculectomy in pediatric glaucoma.

PURPOSE: To evaluate the outcomes of combined deep sclerectomy and trabeculectomy (penetrating deep sclerectomy) in pediatric glaucoma. DESIGN: Retrospective, nonconsecutive, noncomparative, interventional case series. PARTICIPANTS: Children suffering from pediatric glaucoma who underwent surgery between March 1997 and October 2006 were included in this study. METHODS: A primary combined deep sclerectomy and trabeculectomy was performed in 35 eyes of 28 patients. Complete examinations were performed before surgery, postoperatively at 1 and 7 days, at 1, 2, 3, 4, 6, 9, and 12 months, and then every 6 months after surgery. MAIN OUTCOME MEASURES: Surgical outcome was assessed in terms of intraocular pressure (IOP) change, additional glaucoma medication, complication rate, need for surgical revision, as well as refractive errors, best-corrected visual acuity (BCVA), and corneal clarity and diameters. RESULTS: The mean age before surgery was 3.6+/-4.5 years, and the mean follow-up was 3.5+/-2.9 years. The mean preoperative IOP was 31.9+/-11.5 mmHg. At the end of follow-up, the mean IOP decreased by 58.3% (P&lt;0.005), and from 14 patients with available BCVA 8 patients (57.1%) achieved 0.5 (20/40) or better, 3 (21.4%) 0.2 (20/100), and 2 (14.3%) 0.1 (20/200) in their better eye. The mean refractive error (spherical equivalent [SE]) at final follow-up visits was +0.83+/-5.4. Six patients (43%) were affected by myopia. The complete and qualified success rates, based on a cumulative survival curve, after 9 years were 52.3% and 70.6%, respectively (P&lt;0.05). Sight-threatening complications were more common (8.6%) in refractory glaucomas. CONCLUSIONS: Combined deep sclerectomy and trabeculectomy is an operative technique developed to control IOP in congenital, secondary, and juvenile glaucomas. The intermediate results are satisfactory and promising. Previous classic glaucoma surgeries performed before this new technique had less favorable results. The number of sight-threatening complications is related to the severity of glaucoma and number of previous surgeries. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Retinoscopía estática: variabilidad interobservadores entre docentes y estudiantes de optometría en una institución universitaria de Bogotá D.C.

Introducción: el gold estándar para el error refractivo es la retinoscopía. Los docentes de optometría al evaluar estudiantes, aceptan una diferencia de ±0,50D en la refracción pero no se ha evaluado estadísticamente si es adecuado para ametropías bajas y altas. El objetivo fue cuantificar el grado de concordancia interobservadores en retinoscopía estática entre docentes y estudiantes, para ametropías altas y bajas. Metodología: estudio de concordancia entre 4 observadores en 40 ojos, 20 con ametropías altas y 20 con bajas; muestreo no probabilístico por conveniencia. Análisis estadístico con coeficiente de correlación intraclase, confiabilidad 95%, poder 90%, y con método gráfico de límites de acuerdo al 95%. Resultados: concordancia para el equivalente esférico entre docentes 0,96 y entre estudiantes 0,56. En estudiantes concordancia de 0,89 para defectos refractivos bajos y docentes 0,96 para defectos altos. Concordancia entre cuatro examinadores 0,78, defectos bajos 0,86 y para altos 0,67. Margen de error entre docentes ±0,87D y estudiantes ±3,15D. En defectos bajos ±0,61D para docentes y ±0,80D para estudiantes y en defectos altos ±1,10D y ±4,22D respectivamente. Discusión: hubo mayor confiabilidad en retinoscopía entre profesionales experimentados. Se comparó la concordancia entre docentes y estudiantes, por eso puede haberse encontrado menor concordancia que la descrita por otros estudios que compararon entre profesionales a pesar haber sido elegidos por sus buenas calificaciones. Se deben formular estrategias de enseñanza que permitan reducir los márgenes de error obtenidos y mejorar la concordancia entre docentes y estudiantes.

Correlación entre el resultado refractivo post-catarata con la predicción biométrica pre-operatoria

La cirugía de cataratas por Facoemulsificación es tal vez uno de los procedimientos más realizados en la práctica de oftalmología general, sin embargo el resultado refractivo de esta cirugía no siempre llena las expectativas del oftalmólogo y del paciente, es por esto que es de gran importancia observar los resultados post quirúrgicos obtenidos y las distintas variables que pudieron influir en dicho resultado. Objetivo: determinar la capacidad predictiva de la formula biométrica empleada en el preoperatorio con el resultado refractivo post operatorio expresada en porcentajes. Materiales y métodos: se realizó un estudio de correlación basándose en la refracción prevista por la biometría y la refracción encontrada en el post operatorio. Se analizó los diferentes grupos de pacientes miopes, hipermétropes y emétropes en de los rangos de 0,50D, 0,75 D y 1,00D. Resultados: el porcentaje de pacientes que presento 0,50D de diferencia con el previsto fue de 57,7% para el total, 100% para hipermétropes, 53,1% para emétropes, 56,3% para miopes. En el rango de 0,75D 71,2% para el total, 62,5% para emétropes y 81,3% para miopes. En el rango de 1,00D 82,7% para el total, 75% para emétropes y 93,8% para miopes. Conclusiones: la formula SRK/T presento un buen desempeño en todos los grupos encontrándose resultados concordantes con los descritos en la literatura.

Macrodisco y glaucoma en individuos estudiados con tomografía óptica coherente

Introducción: El glaucoma representa la tercera causa de ceguera a nivel mundial y un diagnóstico oportuno requiere evaluar la excavación del nervio óptico que está relacionada con el área del mismo. Existen reportes de áreas grandes (macrodiscos) que pueden ser protectoras, mientras otros las asocian a susceptibilidad para glaucoma. Objetivo: Establecer si existe asociación entre macrodisco y glaucoma en individuos estudiados con Tomografía Optica Coherente (OCT ) en la Fundación Oftalmológica Nacional. Métodos: Estudio transversal de asociación que incluyó 25 ojos con glaucoma primario de ángulo abierto y 74 ojos sanos. A cada individuo se realizó examen oftalmológico, campo visual computarizado y OCT de nervio óptico. Se compararon por grupos áreas de disco óptico y número de macrodiscos, definidos según Jonas como un área de la media más dos desviaciones estándar y según Adabache como área ≥3.03 mm2 quien evaluó población Mexicana. Resultados: El área promedio de disco óptico fue 2,78 y 2,80 mm2 glaucoma Vs. sanos. De acuerdo al criterio de Jonas, se observó un macrodisco en el grupo sanos y según criterio de Adabache se encontraron ocho y veinticinco macrodiscos glaucoma Vs. sanos. (OR=0,92 IC95%=0.35 – 2.43). Discusión: No hubo diferencia significativa (P=0.870) en el área de disco entre los dos grupos y el porcentaje de macrodiscos para los dos grupos fue similar, aunque el bajo número de éstos no permitió concluir en términos estadísticos sobre la presencia de macrodisco y glaucoma.

Differences between naïve and expert observers’ vergence and accommodative responses to a range of targets

Purpose: Vergence and accommodation studies often use adult participants with experience of vision science. Reports of infant and clinical responses are generally more variable and of lower gain, with the implication that differences lie in immaturity or sub-optimal clinical characteristics but expert/naïve differences are rarely considered or quantified. Methods: Sixteen undergraduates, naïve to vision science, were individually matched by age, visual acuity, refractive error, heterophoria, stereoacuity and near point of accommodation to second- and third-year orthoptics and optometry undergraduates (‘experts’). Accommodation and vergence responses were assessed to targets moving between 33 cm, 50 cm, 1 m and 2 m using a haploscopic device incorporating a PlusoptiX SO4 autorefractor. Disparity, blur and looming cues were separately available or minimised in all combinations. Instruction set was minimal. Results: In all cases, vergence and accommodation response slopes (gain) were steeper and closer to 1.0 in the expert group (p = 0.001), with the largest expert/naïve differences for both vergence and accommodation being for near targets (p = 0.012). For vergence, the differences between expert and naïve response slopes increased with increasingly open-loop targets (linear trend p = 0.025). Although we predicted that proximal cues would drive additional response in the experts, the proximity-only cue was the only condition that showed no statistical effect of experience. Conclusions: Expert observers provide more accurate responses to near target demand than closely matched naïve observers. We suggest that attention, practice, voluntary and proprioceptive effects may enhance responses in experienced participants when compared to a more typical general population. Differences between adult reports and the developmental and clinical literature may partially reflect expert/naïve effects, as well as developmental change. If developmental and clinical studies are to be compared to adult normative data, uninstructed naïve adult data should be used.